aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--arch/x86/include/asm/syscall.h14
-rw-r--r--arch/x86/kernel/ptrace.c21
-rw-r--r--include/asm-generic/syscall.h8
3 files changed, 21 insertions, 22 deletions
diff --git a/arch/x86/include/asm/syscall.h b/arch/x86/include/asm/syscall.h
index d82f39bb790..8d33bc5462d 100644
--- a/arch/x86/include/asm/syscall.h
+++ b/arch/x86/include/asm/syscall.h
@@ -1,7 +1,7 @@
/*
* Access to user system call parameters and results
*
- * Copyright (C) 2008 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2008-2009 Red Hat, Inc. All rights reserved.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
@@ -16,13 +16,13 @@
#include <linux/sched.h>
#include <linux/err.h>
-static inline long syscall_get_nr(struct task_struct *task,
- struct pt_regs *regs)
+/*
+ * Only the low 32 bits of orig_ax are meaningful, so we return int.
+ * This importantly ignores the high bits on 64-bit, so comparisons
+ * sign-extend the low 32 bits.
+ */
+static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
{
- /*
- * We always sign-extend a -1 value being set here,
- * so this is always either -1L or a syscall number.
- */
return regs->orig_ax;
}
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 8d7d5c9c1be..7b058a2dc66 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -325,16 +325,6 @@ static int putreg(struct task_struct *child,
return set_flags(child, value);
#ifdef CONFIG_X86_64
- /*
- * Orig_ax is really just a flag with small positive and
- * negative values, so make sure to always sign-extend it
- * from 32 bits so that it works correctly regardless of
- * whether we come from a 32-bit environment or not.
- */
- case offsetof(struct user_regs_struct, orig_ax):
- value = (long) (s32) value;
- break;
-
case offsetof(struct user_regs_struct,fs_base):
if (value >= TASK_SIZE_OF(child))
return -EIO;
@@ -1126,10 +1116,15 @@ static int putreg32(struct task_struct *child, unsigned regno, u32 value)
case offsetof(struct user32, regs.orig_eax):
/*
- * Sign-extend the value so that orig_eax = -1
- * causes (long)orig_ax < 0 tests to fire correctly.
+ * A 32-bit debugger setting orig_eax means to restore
+ * the state of the task restarting a 32-bit syscall.
+ * Make sure we interpret the -ERESTART* codes correctly
+ * in case the task is not actually still sitting at the
+ * exit from a 32-bit syscall with TS_COMPAT still set.
*/
- regs->orig_ax = (long) (s32) value;
+ regs->orig_ax = value;
+ if (syscall_get_nr(child, regs) >= 0)
+ task_thread_info(child)->status |= TS_COMPAT;
break;
case offsetof(struct user32, regs.eflags):
diff --git a/include/asm-generic/syscall.h b/include/asm-generic/syscall.h
index ea8087b55ff..5c122ae6bfa 100644
--- a/include/asm-generic/syscall.h
+++ b/include/asm-generic/syscall.h
@@ -1,7 +1,7 @@
/*
* Access to user system call parameters and results
*
- * Copyright (C) 2008 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2008-2009 Red Hat, Inc. All rights reserved.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
@@ -32,9 +32,13 @@ struct pt_regs;
* If @task is not executing a system call, i.e. it's blocked
* inside the kernel for a fault or signal, returns -1.
*
+ * Note this returns int even on 64-bit machines. Only 32 bits of
+ * system call number can be meaningful. If the actual arch value
+ * is 64 bits, this truncates to 32 bits so 0xffffffff means -1.
+ *
* It's only valid to call this when @task is known to be blocked.
*/
-long syscall_get_nr(struct task_struct *task, struct pt_regs *regs);
+int syscall_get_nr(struct task_struct *task, struct pt_regs *regs);
/**
* syscall_rollback - roll back registers after an aborted system call